Printed circuit boards (PCBs) denote boards just before electric components are mounted. In such a PCB, a circuit line pattern is printed on an electrical insulation board using a conductive material such as copper. That is, PCBs denote circuit boards in which an installation position of each of the components is decided and a circuit pattern connecting the components to each other is printed and fixed on a surface of a flat panel to densely mount various electric devices on the flat panel.
An embedded PCB in which each component is buried in the PCB is being provided.
FIG. 1 is a view of a general embedded PCB.
Referring to FIG. 1, the general embedded PCB 10 includes an electronic device 5 buried between a plurality of insulation layers 1, a conductive buried circuit pattern 2 disposed between the plurality of insulation layers 1, and a via hole connecting circuits disposed in layers different from each other to each other.
A solder or buffer 6 is disposed under the buried electronic device 5, and a pad 7 connected to an external circuit pattern 9 is disposed under the solder or buffer 6. Also, a via 8 connecting the pad 7 to the external circuit pattern 9 is disposed under the buried electronic device 5.
As described above, in a case where the electronic device 5 is mounted within the PCB, a bonding sheet and insulation layer 1 for mounting the electronic device 5 are attached to mount the electronic device 5, and then the bonding sheet is removed.
Here, since an adhesive component of the bonding sheet remains on one surface of the electronic device 5, the adhesive component may affect device characteristics. Thus, a phenomenon in which the circuit pattern 9 is separated together with the bonding sheet may occur to reduce reliability.